Patent GB-1172236-A (GB)
Title: Transfer Means for Analytical Measurement Signals
IPC: G06F17/00
Filed: 1966-12-19
Abstract: 1,172,236. Data recording and processing. INFOTRONICS CORP. Dec.19, 1966 [Feb.28, 1966], No.56701/66. Heading G5R. [Also in Division G1] Apparatus for processing transduced analogue data signals having a wide dynamic range comprising means for recording the signals with identifying data on a magnetic tape and play-back means which feed the signals to an output printer via a circuit which integrates the peak signals. Recorder. - The input signal, which is in the arrangement described is supplied from one of a number of chromotographs, is applied to an input amplifier 22 furnished with a switch in its feedback path which varies its gain by a factor of 10. The amplifier which normally works with an input of up to 50 mV has its gain reduced by this factor by operation of relay 23b either by operation of switch 65 to the 500 mV position or with the switch and its ganged section 65a. in the "auto" position when high level Schmitt trigger 68 determines that the input signal has risen above 50 mV. In this latter position of the switch the relay is controlled via a latched pair of NOR circuits 70, 71 which restore the relay to its initial position when low level trigger 69 indicates that the signal level has dropped to a level corresponding to an input of 40 mV. The output of the amplifier 22 is applied via switch 23a to a voltage to frequency converter 24. The frequency of the output signal of the converter is divided by four in the flip flops 25, 26 and the resulting signal is supplied via NOR gate 27 to head driver 28 and recorded by recording head 29 in a tape data channel. The switch 23a is operated via relay 23 to its data transmission mode described by operation of start switch 35 which via a pair of latched NOR gates 37, 38 de-energizes the relay so that the switch assumes the position shown and also blocks NOR gate 40. The arrangement has two other modes, first a reset mode when switch 34 is operated to energize the relay 23 via the latched gates and the open gate 40. In this mode the input to the converter is from a D.C. source 33 and depends on the position of a signal source identifying switch 32, in addition, with the gate 40 unlocked the signal output which is applied to the recording head has a frequency which is a function of the value of the D.C. signal and a mark/space ratio of 1-7. The second mode is the identification mode switched on by switch 36 for a set time controlled by timer 48 when the arrangement is in the reset mode. In this mode gate 27 is blocked and its input after inversion in gate 41 is applied via now opened gate 42 to the driver 28 and head 29. This signal when selected on playback and then integrated for the set time produces an output representative of the signal identifying integer set by switch 32. During automatic operation the output of the latched gates 70, 71 also control a NOR gate 75 associated with reference oscillator 56 and flip flops 58, 59. The arrangement is such that when the amplifier 22 is switched to operate at normal gain a signal having a mark/space ratio of 1:1 is applied to the second recording head 62 which records in a second tape reference channel and when the amplifier operates on reduced gain the mark/space ratio is changed to 1:7. Playback. - The output from the data channel on head 80 is shaped in the Schmitt Trigger 86, doubled in frequency and applied to frequency voltage converter 90. The output of the demodulator is applied to a differential amplifier 94. The output of the demodulator is applied to a differential amplifier 94. The output of the trigger is also applied to an integrator including resistor 97a and capacitor 97e or 97# which supplies no output when the data signal having an equal mark/space ratio is applied but which supplies a positive output when the identification signal is applied and a negative output when the reset signal is applied. Thus a signal appears on line 103 when the identification signal is transmitted and a signal will be present on line 104 when data is transmitted. The output from the reference channel on head 108 is similarly treated in units 116, 117 and converter 118 and a portion of the output signal is applied to the differential amplifier where any distortion picked up in both channels are combined in the opposite sense and cancel. The output from the trigger 116 is also integrated and provides an output on line 130 indicating that the amplifier 22 in the recorder was operating on low gain when the data signal was recorded. Integration.-The output signal on line 95 from the differential amplifier is passed via a differentiating circuit to Schmitt trigger circuits which detect positive and negative slope in the signal and energize a peak recognition circuit which provides a signal on line 201. The signal is also applied to a voltage-frequency converter 165 and in dependence on the playback speed this supplies a signal either directly or via a "divide by four" circuit 165a, 165b to a pair of NOR gates 200 and 202. The signal on line 130 is processed by the gate 184 and the latched gates 185, 186 to supply an output signal on line 187 to gate 203 whereby when a peak is detected either gate 200 counting pulses into the unit decade 169a or gate 202 counting pulses directly into the tens decade 169b is operated. At the end of the peak the gates 200 and 202 are closed and the count in the counter, indicative of the area under the curve is transferred from the counter, one decade of which is shown in Fig. 9, to the memory 171. At the same time a scanner 176 is energized to supply a series of output pulses each of which gates the output of a decade via a binary coded decimal converted to a solenoid driver which sets up the decade number in a printer. On the final pulse the printer is operated to record the complete number. When the chromotograph identification number is transmitted the integrator is controlled to act as if a peak were detected and the signal count over the preset time provides the identifying integer which is printed in the same way as the peak integral. Means are provided for identifying and printing the number of each peak in a series and for totalling the areas under all the peaks of a series.